The disclosed structures and methods relate to interdigitated capacitors having either a relatively low (e.g., zero) net linear temperature coefficient of capacitance or a relatively low (e.g., zero) net quadratic voltage coefficient of capacitance.
For a given on-chip capacitor, capacitance will vary as a function of temperature and applied voltage. Specifically, capacitance as a function of temperature can be estimated using the following expression:C(T)=C0*(1+Tcc*(T−25)),  (1)where C(T) represents capacitance as a function of voltage, C0 is capacitance value at a temperature of 25 degree Celsius (25° C.), Tcc represents a linear temperature coefficient of capacitance and T represents temperature. Additionally, capacitance as a function of voltage can be estimated using the following expression:C(V)=C0(1+Vcc1*V+Vcc2*V2),  (2)where C(V) represents capacitance as a function of voltage, C0 is capacitance value at voltage of zero volt, Vcc1 represents a linear voltage coefficient of capacitance and is typically equal to zero for an interdigitated capacitor, V represents applied voltage and Vcc2 represents a quadratic voltage coefficient of capacitance. Thus, capacitance will vary linearly as a function of temperature such that the greater the operating temperature range, the greater the variation in capacitance. Furthermore, capacitance will vary both linearly and quadratically as a function of voltage such that the greater the operating voltage range, the greater the variation in capacitance. Additionally, the fact that capacitance varies quadratically as a function of voltage becomes particularly problematic in high voltage technologies. Therefore, it would be advantageous to provide a capacitor (e.g., a simple interdigitated capacitor, also referred to herein as a comb capacitor, or an interdigitated vertical native capacitor) with a specific, relatively low (e.g., zero), linear temperature coefficient of capacitance (Tcc) or quadratic voltage coefficient of capacitance (Vcc2) in order to limit capacitance variation in high temperature and/or high voltage applications.